中文摘要：

提出一种基于偏振延时干涉仪（PDI）的非归零（NRZ）码到归零（RZ）码的全光码型转换方案。理论推导光信号经过PDI时光场的演变过程，分析了码型转换的原理。数值仿真实现了10Gb／s速率下NRZ到Rz码的转换，通过比较得出转换后的Rz码具有更高的接收灵敏度。改变双折射介质的差分群时延可以得到不同占空比的Rz信号输出。

英文摘要：

A scheme that signal format conversion from NRZ to RZ using a polarization delay interferometer （PDI） has been demonstrated. The evolvement of the optical field through PDI and the principle of code con- version is analyzed in theory, signal format conversion from NRZ to RZ under 10Gb/s is achieved to make use of software simulations. Results shows that the converted RZ signal has higher receiver sensitivity. Through adjusting the differential group delay of doubly refracting medium, different duty cycle RZ data has been achieved.